JPS62254499A - Cubicle which stabilizes thermally member such as electronicequipmemt components which is contained in it - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a box for housing a member, such as an electronic device component, containing a plurality of heat sources distributed according to a predetermined drafting method. It concerns a box consisting essentially of insulating material and provided with means of the passive type for dissipating the heat emanating from the components housed therein.

Although the present invention is particularly suited to boxes containing various types of electronic components or circuits, it is not limited to this application, and may be used in general applications where components containing a heat source are housed within the box. Applies to all cases.

The heat source may be composed of an active member such as a transistor or a passive member such as a resistor.

Currently, electronic components are typically housed in metal boxes. The type of metal that makes up these boxes is usually determined by the intended use. All the metals used have a sufficiently high ability to conduct and dissipate the heat dissipated into the box by the electronic components, with the highest heat dissipating components against the walls of the box, or with sufficient heat dissipation. These parts and boxes are described in No. 4,330,812.

If the heat to be dissipated is larger, cooling vanes can be provided on the outer surface of the box walls to increase the effect of convection phenomena.

The heat dissipation carried out in this way is passive as it does not use any auxiliary energy sources.

This passive heat dissipation method may optionally be supplemented by active techniques if the amount of heat to be dissipated exceeds the capabilities of the materials used. These active techniques include internal or external ventilation, the addition of Pettier modules, and the use of variable phase fluid circuits.

It should be noted here that the present invention concerns only passive heat dissipation methods; these techniques may optionally be supplemented by some active techniques if the amount of heat to be dissipated is large. .

As mentioned above, all known passive heat dissipation methods rely on the use of a box consisting essentially of thermally conductive material.

However, some applications may require the use of insulation materials, such as molded composite materials, to form the box. This type of application includes mass gain (mass ga
Examples include boxes for housing electronic equipment components used in all applications where 1.in) is desired, especially in the aerospace field. The use of thermal insulation materials is also advantageous, especially in the field of mass electronics, because of its low cost.

In these particular applications, traditional methods of passively dissipating the heat released within the box cannot be used.

Therefore, if it is not desired to use active techniques, which necessarily result in large weight I and cos I, it is necessary to use new active heat dissipation methods.

The object of the present invention is to provide a box consisting primarily of thermal insulation material with passive heat dissipation means that does not significantly affect the characteristics that justify the use of thermal insulation material, such as the advantages of low weight and cost. The goal is to provide a box with

To this end, the present invention provides a box for parts, such as electronic equipment components, containing a plurality of heat sources distributed according to a predetermined drafting method, which includes a mechanically rigid structure made of a heat insulating material, the structure being a thermally conductive material. a plurality of passive heat evacuation means of flexible material, these means being arranged such that each heat source is in contact with one of the means, said heat evacuation means being arranged on an inner surface of said mechanically rigid a structure; The present invention proposes a box consisting of at least one implant in which the implant is placed.

By selecting the type and size of the heat dissipation means according to the amount of heat dissipated by each heat source and distributing these heat sources appropriately, it is possible that these heat sources are Stabilize.

The implant may be used where the heat source has a relatively low dissipated thermal power, for example a maximum of about 5 W, which is the case for many common electronic components.

To facilitate radial dissipation of heat, each implant preferably has a plurality of branches oriented radially or tangentially to the contact zone between the heat source and the implant.

If the heat emitted by the heat source cannot be completely dissipated by the implant alone, the heat evacuation means pass through the mechanically rigid structure and include at least one insert supporting the radiator on the outside of this structure. It is preferable to include a member).

In that case, each radiator preferably has a plurality of vanes extending at right angles to the mechanically rigid structure and regularly distributed around said insert.

Depending on the specific application, this box may also contain X! electronic components. l
These inserts may be made of silver and/or may be made of silver, so that this protective effect continues even at the point of placement of the inserts, with at least one layer of material that protects against Xt! It may be formed to have an increased cross-section portion under the protective material layer. Coating the outer surface of the protective material with a beryllium film to improve heat dissipation avoids the phenomenon of electrons being ejected through the walls of the box when the box is irradiated with X-rays.

In one particularly advantageous implementation of the invention, at least the inner surface of the mechanically rigid structure is coated with a film of thermally conductive material. In this case, the insert and/or implant will be in contact with this film, facilitating heat dissipation.

Preferably, this film is made of nickel, aluminum,
Made of beryllium, copper or silver. These materials have high conductivity, and the film has a Faraday cage fLfa.
Also give. This Faraday cage protects the electronic components housed inside the box from electromagnetic waves other than XII.

Hereinafter, the present invention will be explained in more detail by giving various non-limiting specific examples based on the accompanying drawings.

m control FIG. 1 shows very simply the box of the invention.

This box is designated as a whole by the numeral 10. This box is the first
The illustrated embodiment comprises a base 12 and a cap or cover 16 secured thereon by any suitable means, such as screws (rt line 14 in Figure 1).

According to the invention, the box 10 houses a component containing a plurality of heat sources that are distributed according to a predetermined drafting scheme within the enclosed space defined by the box. These parts may in particular be electronic components of active or passive type, for example components 18a and 18b of FIG.

These components are electrically connected to components outside the box via electrical conductors such as electrical conductors 20a and 20b of FIG. These electrical conductors pass through the base 12, for example.

In the specific example of FIG.
2 or within the structure by any suitable means.

Usually, the components 18a, 18b are printed circuit 1
9, and the circuit itself is fixed to the box by suitable devices, not shown.

As one of the essential features of the present invention, 18a, 18b
The rigid structure 22, which mechanically protects the parts, is formed by thermal insulation. The fI rod 22 may be formed by molding a thermosetting plastic material such as Bakelite I, polyimide resin, or silicone, optionally reinforced with organic fibers. non-limiting
By way of example, the rigid structure 22 may be formed using polyimide resin reinforced with arbitrarily oriented glass fibers.

This resin is commercially available from 100 companies under the trademark KINEL 5504.

Only some of the components housed in the box 10 constitute the heat source.

These heat source components are further classified into two types depending on whether the heat intensity output produced by each heat source is less than or greater than the maximum heat output that can be dissipated by the cover 16 for a given surface area of said cover corresponding to that heat source. Divided into types.

More precisely, after experimentally measuring the heat exchange parameters (transfer coefficient α and radiation ε) of the material of one or more sides constituting the cover 16, the heat exchange parameters (transfer coefficient α and radiation epsilon) of the material constituting the cover 16 are determined. Calculate the heat output obtained and then, for each type of heat source, determine the law of transfer of this heat output that can be dissipated through the surface of the cover corresponding to that heat source. The shape of the surface is determined by the type of heat source.
For example, in the case of a dot-shaped heat source, ie, a heat source whose surface area in contact with the cover has small values in all directions, a square surface corresponds to the heat source. In the case of a diagonal heat source, the surface has a dark blue elongated rectangular shape.

The maximum heat power that can be dissipated is calculated for each heat source from the above-mentioned movement law by giving each heat source a maximum surface area determined by considering adjacent heat sources and depending on the approved heating. A single heat source may be associated with a larger surface, resulting in a greater maximum amount of heat that can be dissipated than when multiple heat sources are placed adjacently. The distribution of heat sources within the box is advantageously carried out with the aforementioned considerations in mind.

In this way, heat generated from some of the heat sources located within the box is dissipated through the cover material.

However, the dissipation of some of these heat sources is usually insufficient, which necessitates the box 10 being equipped with supplementary means to passively dissipate the heat dissipated into the box 10 by these heat sources. be.

These auxiliary means depend on the amount of heat produced by each heat source.
Each heat source is constructed by an implant attached to or molded onto the inner surface of the rigid structure 22, or by an insert passing through said structure and coplanar with the outer radiator. In either case, these various auxiliary means are formed from thermally conductive materials such as metals. - By way of example, the implant and radiator may be constructed of aluminum alloys such as 02GN and 804G1, respectively, and the inserts 1~ may be constructed of copper.

In FIG. 1, part 18a constitutes a heat source of relatively low intensity, yet it is necessary to provide the box with supplementary heat dissipation means. In this case, the heat dissipated from this part is transferred to a metal implant 24 disposed on the inner surface of the cover 16.
dissipated by placing it in contact with the

Part 18b constitutes a greater intensity heat source.

In this case, heat is removed by placing this part in contact with the metal insert 26. The insert extends through the cover 16 and is shown in one embodiment of the implant 24 of the present invention in which the heat source is generally point-shaped. Part 18a and Imblanc 1-2
4 and the contact surface or contact zone is relatively limited in either direction, for example circular as in FIG. 2b. The contact zone thus defined between part 18a and implant 24 constitutes the center of this implant. The implant 24 further includes a plurality of branches 24a to radially (FIG. 2b) or tangentially (FIG. 2c) dissipate heat dissipated from the component. These branches extend radially to the central contact zone and are regularly distributed around this zone. In the embodiment shown in FIG. 2b, the number of these branches is six, so that the implant 24 exhibits the shape of a star with six arms or branches, provided that the number of branches of the implant may be any number other than six. If the heat emitted from the component is smaller, the number may be four, for example. The shape of the implant is determined by considering the amount of heat to be discharged and by increasing the size of the surface (Wt) and heavy EL (
weight) is determined for each specific case.

Figures 3a and 3b illustrate an implant 24° used to evacuate heat emitted from a component such as a card or board 18a that is substantially linear and supports a plurality of electronic circuits. A specific example is shown. In this case, the part 18°a and the implant 24' come into contact along a long, relatively narrow rectangular surface.

In this case, the implant 24' comprises a rectangular central part surrounding the contact zone between the card 18°a and the implant, the implant 24' further comprising a plurality of branches 24'a on either side of the central part. , these branches extend perpendicularly to this central part with constant spacing between them.

In this case, the structure of this implant (shape, mass,
If the surface area, etc.) is suitable for the amount of heat dissipated by the card or board 18'a, these branches also provide for the removal of heat to the outside, so that the card 18'a is thermally stabilized. Of course, other shapes of implants may be used, especially if the heat source is not substantially point-like or linear.

As an example, in the case of a nearly point-like load discharging a heat output of 2.4 W, each branch has a length of 30 m and a width of 10 m, and the weight of the implant is 0.7 g. A cruciform implant can be used. For example, in the case of a nearly point-like charge that emits a charge equivalent to 4W, the branch is set to 6
An implant is used in which each pair of opposing branches has dimensions of 60 mm x 10 mm and the weight of the implant is 2.2 g.

This method is suitable for heat sources with a heating power of less than 5W.

The implant 24, 24° may be secured to the inner surface of the box cover by any suitable means. Inblan I.24 of FIG. 2a is adhesively secured to said inner surface. On the other hand, the Inblan I-24'' shown in Fig. 3a has a portion inserted and fixed into the body during the molding of the box structure.

Implants 24 and 24' also include parts 18a and 1
It can also be advantageously used as a support means for 8°a. For this purpose, these parts are fitted into the implant (FIGS. 3a and 3b).

FIGS. 4a and 4b show an example of an insert 26 and a corresponding radiator 28 in an enlarged view. In the case of a dotted heat source, the insert 26 is constituted by a cylindrical metal block made of copper, for example. This block penetrates the wall of the cover 16 and the part to be cooled 18b
closely adhere to. For example, screw 3 is placed on top of this metal block.
The radiator 28 may be secured to the outside of the whistle by any means such as 0.

The radiator is fixed to the insert in such a way that sufficient thermal conductivity is obtained at the contact level.
8 includes a base 28a, for example in the shape of a six-branched star, which rests on the insert 26 and on the outer surface of the box 16 by screws 30.

This base 28a is provided with m-shaped vanes 281) on each branch, which protrude at right angles to the outer surface of the box.

The branches of the base 28a and the vanes 28b are regularly distributed about the axis of the insert 26.

Of course, the size of the insert 26tR metal block is
The size of the base and blades constituting the radiator Z8, as well as the size, are determined depending on the heat output to be dissipated. - As an example, the radius of the radiator is 61, the iii is 8.2g, and the size of each branch pair of the base 28a is 601111X10m
s, when the radius of each blade 28b is 2511IIl,
The tR insert may have a weight of approximately 3.9g. From such an assembly, depending on the permissible temperature T, an output of 10~
12W of heat can be dissipated. - As an example, if T is 60°C, approximately 7W of heat will be dissipated.

Of course, the schematic arrangement of the heat sources within the box is predetermined such that the f4 separation between the heat sources increases as the dissipated heat output increases.

FIG. 5 shows another embodiment of the invention. In this embodiment, the cover 16 does not consist solely of the mechanically rigid structure 22, but also comprises an outer layer 36 of material that protects the components contained within the box 10 from X-rays.

For details on the structure and manufacturing method of this protective layer 36, see 19
L'^erospatiale filed on April 16, 1986
(S, H, 1,) French Patent Application No. 8605442
Please refer to the issue.

X like this! ! If protection against is required, it must be ensured that this protection effect continues even at the level of the insert 26, which penetrates the protective material layer.

To obtain frost impermeability to X-rays, the insert 26 may be made of silver. For example, the thickness of this metal box is 1
．． This is because 73n+m provides a sufficient damping effect in a wide range of applications.

The opacity can be achieved regardless of the photon trajectory given the required filter thickness, depending on the type of metal of the insert 26 (
Copper, molybdenum, tin, silver,! It can also be obtained regardless of F). To this end, as shown in FIG. 5, the cross section of the insert 26 is increased below the protective layer of material 36, ie at the penetration level of the structure 22.

The geometrical conditions of the insert 26 as described above also apply to the outer [
The 3B constituent material is applied as long as it satisfies the rigidity conditions required for the structure 22. In this case, therefore, the increased cross-section of the insert 26 is located below the wall of the material layer 36. This layer satisfies the rigidity conditions and the X-ray protection conditions, but has low thermal conductivity, and the rigidity and X-ray protection conditions are low. ! The choice of using one material that simultaneously satisfies these conditions or two materials that satisfy these conditions separately depends on the desired stiffness and radiopacity.

FIG. 5 also shows that the thermal stability of the heat source contained within the box can be improved by coating at least a portion of the interior surface of the structure 22 with a thermally conductive material [38, such as a metal]. That is, implant 24 and insert 26 are in contact with this layer 38, thereby improving heat dissipation.

If box 10 includes multiple inserts 26, a layer of thermally conductive material may also be provided on the outer surface of the box, ie, outside of layer 36 in FIG.

The thickness of layer 38 may be approximately 0.1 mm, for example.

Preferably, metals such as minilum, beryllium, copper or silver are used.

It should be noted that this layer 38 also constitutes a Faraday cage, which, in addition to its heat dissipation function, also serves to protect the circuitry housed within the box against electromagnetic waves other than X-rays. .

Also, if a layer such as layer 38 is placed on the outside of coating 36 and this layer is composed of beryllium, when the box is irradiated with X-rays, the anti-Xli! The phenomenon of electrons being transmitted through the material constituting the protective sheath 136 is avoided.

Of course, the present invention is not limited to the specific examples described above, and various modifications are possible.

In particular, as already mentioned, the heat source placed within the box of the invention may be any type of heat source, not just an electronic component.

Also, the present invention is independent of the shape of the box. This shape is essentially 3iL depending on the parts housed in the box - and Fr! Layers such as J38 can be used regardless of the construction of the box; one or two layers such as J738 can be used particularly in boxes such as those shown in FIG.

[Brief explanation of drawings]

Figure 1 is a simplified cross-sectional view of a first embodiment of the box of the present invention;
Figures a, 2b and 2c are enlarged side and front views, respectively, of two embodiments of implants placed on the inner surface of the box to dissipate heat emanating from the dot-like parts; , 3a and 3b show a second embodiment of an implant for dissipating heat emanating from a generally linear component.
Illustrations similar to figures a and 2b, figures 4a and 4b
The figures show an enlarged side view and a front view, respectively, of an insert and a radiator which, according to the invention, ensure dissipation of heat dissipated from components that dissipate amounts of heat that are not completely removed by the implant; FIG. FIG. 1 is an explanatory diagram similar to FIG. 1 showing a second specific example of the invention. 12...Base, 16...Cover, 1
8a, 18b... Parts, 24... Imblanc l-126... Insert, 28...
...Radiator, 36... X-ray protection material layer, 38... Heat conductive material layer.

Claims (9)

[Claims] (1) A box containing a member, such as an electronic device component, containing a plurality of heat sources distributed according to a predetermined drafting method, the box including a mechanically rigid structure made of a heat insulating material, and the box containing a mechanically rigid structure of a heat insulating material. a plurality of passive heat evacuation means of thermally conductive material, the means being arranged such that each heat source is in contact with one of the means, said heat evacuation means being in contact with an inner surface of said mechanically rigid structure; such a box having at least one implant placed therein. (2) Each implant has a plurality of branches, the branches being oriented radially or tangentially with respect to the contact zone between one of the heat sources and the implant. box. 3. The box of claim 1, wherein the heat evacuation means has at least one insert passing through the mechanically rigid structure and supporting a radiator on the outside of the structure. (4) Each radiator has a plurality of vanes oriented at right angles to the mechanically rigid structure and regularly distributed around the insert.
The box mentioned in section. 5. The box of claim 3, further comprising at least one layer of material that protects said member from X-rays. (6) The box of claim 5, wherein each insert is formed of silver. 7. The box of claim 5, wherein each insert has an increased cross-section portion below the layer of X-ray protective material. (8) At least the inner surface of the mechanically rigid structure is coated with a film of a thermally conductive material.
The box mentioned in section. 9. The box of claim 8, wherein said film is formed of a material selected from nickel, aluminum, beryllium, copper and silver.